Unsaturated ketones have numerous applications in organic chemistry. They are generally used as additives during the manufacture of perfumes. Various methods are available in the art for the preparation of unsaturated ketones.
Generally, unsaturated ketones are prepared by aldol condensation of aldehydes with ketone using sulfuric acid as a catalyst. However, this process produces huge amount of toxic wastes so that large amount of effluent treatment is required which results in increase in cost of manufacturing. Also, the yield of the final product the unsaturated ketone is less.
EP1000922B1—Provides for a process of preparing unsaturated ketones by reacting the corresponding α,β-unsaturated alcohols with alkyl acetoacetates in the presence of from 0.1 to 5 mol %, based on the alkyl acetoacetate to be reacted, with an organic aluminum compound as catalyst with elimination and continuous removal by distillation of the carbon dioxide which forms during the reaction and of the alcohol which is eliminated from the acetoacetate in a reactor system with fitted fractionating column, wherein the α,β-unsaturated alcohol is introduced with less than 10% by weight of an inert solvent and with less than 0.5% by weight of a liquid which has a boiling point between that of the alkyl acetoacetate and that of the alcohol to be eliminated there from into the reaction vessel together with the organic aluminum compound, and the alkyl acetoacetate is metered into this mixture, a reaction temperature which is as constant as possible at between 175° C. and 220° C. is adjusted and during the reaction the content of alkyl acetoacetate in the reaction mixture is adjusted to a value which is as constant as possible at between 0.1 and 10% by weight.
The above process is very cumbersome and involves too many steps and the reaction is carried out at a high temperature.
Hence there is a need for a process for preparation of the unsaturated ketone that solves at least one of the problems as defined above and other problems related to the preparation of the unsaturated ketone.